Donald Trump could make history once again—this time as the first former U.S. president ever to be criminally indicted. A Manhattan grand jury could return an indictment as early as this week in a case involving his alleged hush-money payment to former porn star Stormy Daniels. Daniels says she and Trump had an affair; Trump denies this. “Like all things with Trump, it’s unprecedented,” says Barbara Perry, a presidential historian at the Miller Center at the University of Virginia.